The original equipment dual mass flywheel puts
a major damper on engine performance. The flywheel design uses additional mass to
prevent the gears in the transmission from vibrating in response to the
combustion energy pulses that are transmitted by the crankshaft.

If one is willing to accept some noise at
idle in trade for increased dynamic power output, a lighter flywheel might be
right for you. The transmission rattle noise will vary depending on the smoothness of the
engine's idle and the clearances in the transmission. Engines with excellent idle quality will be quieter. Most
installations are the quietest if a 750 rpm idle speed is utilized. There will
also be some low level growl from the transmission when accelerating lightly
in the 750 to 2500 rpm range.

An increase in dynamic power can be measured
on a dynamometer that measures the rate of acceleration of an engine. Inertia
dynamometers such as the Dynojet (tm) can quantify dynamic power. The driver
of a ZR-1 with a significantly lighter flywheel will observe that the car
accelerates faster in the lower gears. The greater the rate of engine acceleration, the more noticeable the improved acceleration
will be. This is especially noticeable in the first and second gears.

The power to weight ratio of a 400 chp ZR-1
is approximately 9 lbs./chp (3600 lbs./400hp = 9lbs./chp). Based on this power
to weight ratio, the car would need to be lightened 135 pounds to match the
improvement in acceleration that is available with 24 pounds less flywheel
weight (15 hp x 9 lbs./hp = 135 lbs.).

The original equipment disk and pressure
plate are an excellent clutch. The OE disk and pressure plate are suitable for
drag racing with street tires with up to 550 crankshaft hp.

The OE transmission lubricant is 5W-30
viscosity mineral based oil. We have found that Red Line Shock
Proof Heavy lubricant reduces the gear rattle the most. A synthetic lubricant is
also more
stable for viscosity as temperature increases. As a result, the tendency for the gear
rattle to increase with operating temperature is reduced.

The cost of the Fidanza flywheel, balancing,
correct length bolts, washers and Shock Proof lubricant is $720. Labor for installation is $552. The
installed price is $1272. If the flywheel upgrade is installed along with any
other service or upgrade that involves removal and replacement of the
flywheel, the labor overlaps with the other service and therefore there is no
$552 installation charge.

More information about drive line
inertia reduction from another source.

Automotive engineer and popular automotive
author David Vizard published an article in the February 2006 issue of Popular
Hot Rodding magazine.

They tested two late '80's Mustangs, one
with 240 whp and another with 425 whp. Flywheel weight was reduced by 12.7
pounds. On the Dynojet dynamometer, both cars produced about +15 whp. The cars
were also drag race tested. The ET's were both approximately -.1 second. A
back issue copy of the magazine can be purchased at
www.popularhotrodding.com.